Question

The Taylors Have recorded their weekly grocery expenses for the past 16 weeks and determined that the mean weekly expense was 85.50. Later , Mrs.Taylor discovered that 1 weeks expense of $77 was incorrectly recorded as $37. What is the correct mean ?

The correct mean is $ ____?

Answer 1

The correct mean is $88
Work backward:
85.5x16=1368
1368-37 (the incorrect value) + 77= 1408
1408/16=$88

Answer 2

Answer: Hence, the correct mean is 88.

Explanation:

Since we have given that

Number of weeks = 16

Mean of weekly expense for 16 weeks = 88.50

Total weekly expenses is given by

$Mean=\frac{Total\ expenses}{Number\ of\ Weeks}\\\\85.50=\frac{Total\ expenses}{16}\\\\85.50\times 16=Total\ expenses\\\\\ 1368=Total\ expenses$

According to question, we get that she recorded $77 as $37 .

So, our equation becomes,

$1368+77-37=1368+40=\ 1408$

so, correct mean will be

$Mean=\frac{1408}{16}=88$

Hence, the correct mean is 88.